Addition crosslinked silicone materials typically comprise a divinyl terminated polydimethylsiloxane, a polydimethylsiloxane containing at least 3 SiH-groups per molecule, a Pt-based catalyst and optionally fillers, retarders and other typically used auxiliaries.
For the control of the setting reaction short-chained divinylsiloxanes, as e.g. divinlytetramethyldisiloxane, are typically applied as retarders (see e.g. U.S. Pat. No. 4,096,159, U.S. Pat. No. 5,403,885 and US 2005/0171233). Further components which can be used are alkynes or alkynols as described e.g. in EP 1 741 420 A1. Other components for retarding the hydrosilylation reaction are molecules or compounds which are capable of forming complexes with the platinum catalyst, as e.g. phosphorus compounds, as known from high temperature addition-curable silicone compositions (e.g. as described in U.S. Pat. No. 5,380,812).
Allyl- and methallylsilanes as hydrogen scavengers in addition cured silicone impression materials are described in U.S. Pat. No. 7,700,712 and the use of di, -tri-, and tetraallylsilane for increasing the crosslinking density of impression materials are described in US 2007/0060717.
Dental silicone-based impression materials comprising an addition- and condensation-curing mechanism are described e.g. in WO 2002/058641 and U.S. Pat. No. 7,572,842.